Telegraph system



' Aug. 23, 1932. I F, G, HAL DEN 1,873,883

TELEGRAPH SYSTEM Filed June 15, 1929 AMPLIFIER INVENTOR FREDERICK o. HALLDEN ATTOR N EY Patented Aug. 23, 1932 3 entree STATES PATENTOFFICE,

FREDERICK e. HALLDEN, or JAMAICA, NEW YORK, assrenon T POSTAL TELEGRAPH- CABLE COMPANY, OF NEW YORK, N. Y., A CORPORATION OF CONNECTICUT TELEGRAPH SYSTEM Application filed June 15, 1929. Serial No. 371,256.

This invention relates to telegraph systems. More particularly the invention applies to printing telegraph systems wherein thereceived signals are subject to attenuation or other distortion. i v

In operating a radio printing telegraph apparatus the received signals often become soattenuated, that is, so reduced in strength,

anddistorted due to atmospheric disturbancesthat perfect reception athigh speed is difficult. When an arc transmitter is used this'distortion is contributed to by WhahlS generally termed bubbling, or a momentary failure of the oscillations in: thetransmitter. Some of the causes of this failure are. impurities in the electrodes, non-concentricity of the revolving electrode, varying arc gap, and moisture inthe arc chamber;

It is customary in a-distributor fora radio telegraph receiver, to use receiving segments which are much shorter than the transmitting segments. In this way perfectreception may be had when signals are badly distorted as only a small part of the transmitted signal is required to actuate the printing mechanism. the short'receiving segments being oriented in relationto the incoming signals so as to use the central part ofthe signal which is less subject to distortion than outer portions. The unused part of the signal falls between the receiving segments and is lost.

The system 'ust described has the disadvantage that I should the central portion of the received signal be weak or if it be missing entirely the impulse will be lost even though the rest of that impulse might be strong enough to operate the receiving mechanism;

The presentinvention provides an arrangement for preventing the loss of an impulse when the portion which should'fall' on the receiving segment is too weal: to operate the receiving mechanism or entirely missing.

In the accompanying drawing there is shown a circuit arrangement representing a preferred embodiment of the invention, of which, i

-.'A-I'llustrates the. wave coming from the amplifier of a radio receiver when alternate marking impulses'are being received.

Y-,Represents the amplifier of a radio receiver. 1'

Beltepresents the coil of a relay which is controlled by the amplifier Y.

I CIs the tongue of relay ,B.

NIs a spring attached to C.

I Is a Polar printing relay having two coils G and H. One side'of coil G is connect ed to the common side of a sourceor" potential andthe other side to tongue C of relay B.

D-Is a solid ring of a receiving distributor shown developed for the sake of clearness. Associated with Dis a segmented ring I, and a brush'K. 'D'is connected to the tongue of relay F. Brush K as it moves along D'connects D to the segments I in sequence.- Se-' lecting magnets J are each. connected in series with a segment I and a common return circuit to negative-potential. D is also connected with a solid ring E. The segments of ring Mare connected to one side of coil H of relay F. Brush L connects the segments'M to ring E as it rotates. The other side of coil H is connected to negative potential.

The operation of the arrangement disclosed is as follows:

If a signalconsisting of alternating marking and spacing impulses such as represented by curve A passes through the coils of relay B, tongue C will move between its contacts which are connected to opposite poles of a source of potential. Coil G of relay 'F is in series with tongue C and the common side of the battery. Each'movement of C will reverse the direction of the current through Gr and the tongue of F will be moved from side to side accordingly. Assume a marking impulse is received. G will move to its right hand or negative contact and a circuit will be completed through G'of relay F to the common side of the battery. The tongue of relay F will move to its marking contact placing positive potential on ring D. Brush K as it passes along D will complete a circuit from D through a segment I through a selecting magnet J, which will be operated, to negative potential. i If the next impulse is spacing, as in curve A, tongue C of'relay B will be moved to its spacing side, reversing the direction of the current through coil G which will cause the tongue of F to move to its spacing side. As there is no potential on the spacing side of F there will be no potential applied to the segment as the brush passes over it and the selecting magnet will remain unoperated.

Brush L rotates in fixed relation to brush K. L makes contact with segments M so timed that L is at the beginning of a segment M when the first part of an impulse is received. If brush L rests on any part of segments M at the time relay F moves-against its marking contact, a circuit will'be completed from the marking contact and tongue of relay F, ring E, brush L, segments M, coil H of relay F to negative. The current through winding H is of such direction and magnitude as to prevent the armature of relay F from moving away from its marking contact even though the armature of relay B moves from its marking contact which would ordinarily reverse the operation of relay F. V

As brush K leaves segment I withwhich it has been in contact, brush L leaves segment M, interrupting. the locking circuit through coil II andpermitting relay F to be again controlled by relay I Assuming that part of amarking impulse as designated by section a: of curve A is missing or distorted, and that brush K- has just reached segment I as the distorted part of the signal is passing through the coils of relay B. Tongue C under the influence of spring N will move to its spacing contact, reversing thecurrent through coil G of relay F. But the tongue of relay F having been moved to its marking contact by the first part of the marking pulse, remains on its marking contact under the influence of the stronger current through coil H until brush L leaves seg ment M, interrupting the locking circuit when relay F will again be under the'control of relay B. In this manner marking current is kept continuously on ring D after the first response of relay B to a marking signal thus preventing the loss of an impulse which would otherwise occur if the tongue C of relay B had left its marking contact when K was passing over segment M.

What I claim is l 1. In a signalling system, a receiving relay responsive to received impulses, a local relay initially and directly operable by said receiving relay, a distributor, means controlled by said distributor for maintaining said local relay in its operated position both independently of said receiving relay and for a predetermined portion of the impulse time remaining after the operation of said local relay. V

2. In a signalling system, a. receiving relay responsive to received impulses, a local relay initially and directly operable by said receiving relay, a distributor, means controlled by said distributor for maintaining said local relay in its operated position both independently of said receiving relay and for a predetermined portion of the impulse time remaining after the operation of said local relay, and for thereafter replacing said local relay under control of said receiving relay.

3. In a signalling system, a receiving re-v lay responsive to received impulses, a local relay initially and directly operable by said determined portion of the impulse time remaining after the operation of said local relay.

4:. In a signalling system, a receiving relay responsive to received impulses, a local relay initially and directly operable by said receiving relay, a distributor, means controlled by said distributor for maintaining said local relay in one of its operated positions both independently of said receiving relay and for a predetermined portion of the impluse time remaining after the operation ofsaid local relay, and for thereafter replacing'said local relay under control of said receiving relay.

5. In a signalling system, a receiving relay responsive to received impulses, a local relay initially and directly operable by said receiving relay, a distributor and a plurality of selecting relays, means controlled by said distributor for maintaining said local relay in its operated position both independently of saidreceiving relay and for a predetermined portion of the impulse time remaining, after the operation of said local relay, and for operating a predetermined selecting relay while said local relay is maintained in saidoperated position.

6. Ina signalling system, a receiving relay responsive" to received impulses, a local relay"initially and directly operable by said receiving relay, a distributor and a plurality of selecting relays, means controlled by said distributor for maintaining said local relay in its operated position both independently of said receiving relay and for a predetermined portion of the impulse time remaining after the operation of said local relay, for operating. a predetermined selecting relay while said local relay is maintained in said operated position, and for thereafter replacing said. local relay under control of said receiving relay.

7 In a radio signalling system, means for receiving signals, a receiving relay operable thereby, a local relay directly responsive to the operation of said receiving relay, a distributor and a plurality of selecting relays, meansincluding said local relay and said In test1mony whereof I aflix my signature. I

FREDERICK G. HALLDEN. 

